Tutorial: CWL → Nextflow Round-Trip

Convert a CWL workflow to Nextflow, edit it, then convert back and verify no information loss.

1. Prepare example

curl -LO https://raw.githubusercontent.com/common-workflow-language/workflows/v1.2/v1.0/v1.2/example_workflows/varscan2/varscan.cwl
curl -LO https://raw.githubusercontent.com/common-workflow-language/workflows/v1.2/v1.0/v1.2/example_workflows/varscan2/varscan-job.yml

2. Convert CWL → Nextflow

wf2wf convert -i varscan.cwl -o main.nf --out-format nextflow --report-md

3. Edit in Nextflow (optional)

Open main.nf, change container tag, save.

4. Convert back to CWL

wf2wf convert -i main.nf -o roundtrip.cwl --out-format cwl

5. Check loss report

wf2wf validate roundtrip.cwl.loss.json

All entries should be reapplied — confirming metadata round-tripped.